Parsimonious modelling of winter season rainfall incorporating reanalysis climatological data

Several Markov Modulated Poisson Process (MMPP) models are developed to describe winter season rainfall with parsimonious parameter use. We propose a methodology for determining the best form of seasonal model for fine-scale rainfall within a MMPP framework. Of those proposed here, a model with a fixed transition rate is shown to be superior over the other MMPP models considered. The model is expanded to include covariate data for sea-level air pressure, relative humidity, and temperature using reanalysis data over 14 years from the coordinates covering the Bracknell rainfall collection site in England. Results are compared using the likelihood ratio test and the second-order properties of aggregated rainfall

Eliciting Dirichlet and Gaussian copula prior distributions for multinomial models

In this paper, we propose novel methods of quantifying expert opinion about prior distributions for multinomial models. Two different multivariate priors are elicited using median and quartile assessments of the multinomial probabilities. First, we start by eliciting a univariate beta distribution for the probability of each category. Then we elicit the hyperparameters of the Dirichlet distribution, as a tractable conjugate prior, from those of the univariate betas through various forms of reconciliation using least-squares techniques. However, a multivariate copula function will give a more flexible correlation structure between multinomial parameters if it is used as their multivariate prior distribution. So, second, we use beta marginal distributions to construct a Gaussian copula as a multivariate normal distribution function that binds these marginals and expresses the dependence structure between them. The proposed method elicits a positive-definite correlation matrix of this Gaussian copula. The two proposed methods are designed to be used through interactive graphical software written in Java

First report of field outbreaks of ergot-alkaloid toxicity in South Africa

Outbreaks of clinical disease caused by the ingestion of ergotized Lolium rigidum (annual ryegrass), which resulted in a substantial loss in production, have been reported. A number of outbreaks of a hyperthermia syndrome in cattle, characterized by severe loss in milk production, loss of body mass and reduced fertility, are described. In one major outbreak in March to April 1994, a milling company reported that 2 646 dairy cows on 29 farms had developed clinical signs. In this outbreak, significant levels of ergotamine, ergosine, ergocornine and ergocryptine were found in the milled dairy rations fed to the affected cows. Barley screenings containing ergotized annual-ryegrass seed was identified as the toxic component and probable source of the ergot alkaloids in the ration. The clinical syndrome was reproduced experimentally by feeding suspected feed to a group of nine high-producing Ayrshire cows. An outbreak of gangrenous necrosis of the extremities in young cattle in the winter of 1987 was also suspected of having been caused by ergot alkaloids in grain screenings.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat X Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

First urology simulation boot camp in the United Kingdom

Objective: Simulation is now firmly established in modern surgical training and is applicable not only to acquiring surgical skills but also to non-surgical skills and professionalism. A 5-day intensive Urology Simulation Boot Camp was run to teach emergency procedural skills, clinical reasoning, and communication skills using clinical scenario simulations, endoscopic and laparoscopic trainers. This paper reports the educational value of this first urology boot camp. Subjects and methods: Sixteen urology UK trainees completed pre-course questionnaires on their operative experience and confidence level in common urological procedures. The course included seven modules covering basic scrotal procedures, laparoscopic skills, ureteroscopy, transurethral resection of the prostate and bladder tumour, green light laser prostatectomy, familiarisation with common endoscopic equipment, bladder washout to remove clots, bladder botox injection, setting up urodynamics. Emergency urological conditions were managed using scenarios on SimMan®. The main focus of the course was hands-on training using animal models, bench-top models and virtual reality simulators. Post-course assessment and feedback on the course structure and utility of knowledge gained together with a global outcome score was collected. Results: Overall all the sections of feedback received score of over 4.5/5, with the hands-on training on simulators getting the best score 4.8/5. When trainees were asked “The training has equipped me with enhanced knowledge, understanding and skills,” the average score was 4.9/5.0. The vast majority of participants felt they would recommend the boot camp to future junior trainees. Conclusion: This first UK Urology Simulation Boot Camp has demonstrated feasibility and effectiveness in enhancing trainee’s experience. Given these positive feedbacks there is a good reason to expect that future courses will improve the overall skills of a new urology trainee

Evolution of 18F-FDG-PET/CT findings in patients following COVID-19 pneumonia: An Initial Investigation

Background: The evolution of pulmonary 18F-FDG uptake is unknown in patients with pneumonia due to SARS-CoV-2 (COVID-19 pneumonia) and in those with persistent respiratory symptoms post-COVID-19 termed Post-COVID-19 Lung-Disease (PCLD). The aim of this study was to assess the temporal evolution of pulmonary 18F-FDG uptake and identify a potential role for the use of 18F-FDG-PET/CT imaging in the management of these patients. Methods: Clinical data and CT imaging of all patients that underwent 18F-FDG-PET/CT imaging at UCLH, Lon-don during the UK pandemic were reviewed to find evidence of active or recovered SARS-CoV-2 infection. Results of PCR tests were used where available. Patients were divided in to acute (early and late) COVID-19 pneumonia, PCLD and asymptomatic recovery. 18F-FDG uptake in the lungs was measured as a target-to-background ratio (SUVmax/SUVmin) TBRlung which was compared to temporal-stage and plasma CRP. Results: There were 50 patients in total (median 61y, range 18-87y, 32-male): 23 incidental acute COVID-19 pneumonia cases identified retrospectively (8 Early, 15 Late), 9 asymptomatic recovered patients, and 18 cases performed for PCLD. In acute COVID-19 patients <3 weeks since disease onset TBRlung was strongly correlated with time since disease onset (rs=0.81, p<0.001)

Neurons Controlling Aplysia Feeding Inhibit Themselves by Continuous NO Production

Neural activity can be affected by nitric oxide (NO) produced by spiking neurons. Can neural activity also be affected by NO produced in neurons in the absence of spiking?Applying an NO scavenger to quiescent Aplysia buccal ganglia initiated fictive feeding, indicating that NO production at rest inhibits feeding. The inhibition is in part via effects on neurons B31/B32, neurons initiating food consumption. Applying NO scavengers or nitric oxide synthase (NOS) blockers to B31/B32 neurons cultured in isolation caused inactive neurons to depolarize and fire, indicating that B31/B32 produce NO tonically without action potentials, and tonic NO production contributes to the B31/B32 resting potentials. Guanylyl cyclase blockers also caused depolarization and firing, indicating that the cGMP second messenger cascade, presumably activated by the tonic presence of NO, contributes to the B31/B32 resting potential. Blocking NO while voltage-clamping revealed an inward leak current, indicating that NO prevents this current from depolarizing the neuron. Blocking nitrergic transmission had no effect on a number of other cultured, isolated neurons. However, treatment with NO blockers did excite cerebral ganglion neuron C-PR, a command-like neuron initiating food-finding behavior, both in situ, and when the neuron was cultured in isolation, indicating that this neuron also inhibits itself by producing NO at rest.Self-inhibitory, tonic NO production is a novel mechanism for the modulation of neural activity. Localization of this mechanism to critical neurons in different ganglia controlling different aspects of a behavior provides a mechanism by which a humeral signal affecting background NO production, such as the NO precursor L-arginine, could control multiple aspects of the behavior

A frequentist framework of inductive reasoning

Reacting against the limitation of statistics to decision procedures, R. A. Fisher proposed for inductive reasoning the use of the fiducial distribution, a parameter-space distribution of epistemological probability transferred directly from limiting relative frequencies rather than computed according to the Bayes update rule. The proposal is developed as follows using the confidence measure of a scalar parameter of interest. (With the restriction to one-dimensional parameter space, a confidence measure is essentially a fiducial probability distribution free of complications involving ancillary statistics.) A betting game establishes a sense in which confidence measures are the only reliable inferential probability distributions. The equality between the probabilities encoded in a confidence measure and the coverage rates of the corresponding confidence intervals ensures that the measure's rule for assigning confidence levels to hypotheses is uniquely minimax in the game. Although a confidence measure can be computed without any prior distribution, previous knowledge can be incorporated into confidence-based reasoning. To adjust a p-value or confidence interval for prior information, the confidence measure from the observed data can be combined with one or more independent confidence measures representing previous agent opinion. (The former confidence measure may correspond to a posterior distribution with frequentist matching of coverage probabilities.) The representation of subjective knowledge in terms of confidence measures rather than prior probability distributions preserves approximate frequentist validity.Comment: major revisio